Vapor recovery nozzle

ABSTRACT

A vapor recovery nozzle for dispensing fuel, such as gasoline, that can be latched to the filler neck of a tank to be filled. An articulated seal is provided that sealingly engages the filler neck and, when so engaged, forces a piston relatively toward the nozzle to open the flow passageway through the nozzle for the vapors. A valve is provided that is actuated by the piston which, when the nozzle is not in the filler neck, closes to prevent the escape of any vapors that might be contained in the vapor recovery system. Furthermore, the piston carries a valve operating means that functions in conjunction with a flow valve that is located in a conduit extending through the nozzle. This conduit is utilized to sense when the liquid level in the tank rises above the end of the conduit extending from the nozzle to automatically shut off the nozzle and prevent flow of fuel therefrom. The arrangement of the nozzle is such that the vapor recovery passageway extending therethrough is sealed to prevent the entrance of air or other vapor into the system except as may come from the fuel tank.

United States Patent 191 Giardini et al.

[ VAPOR RECOVERY NOZZLE [75] Inventors: Virgil Victor Giardini, Connersville,

lnd.; Richard Gordon Bisker, Salisbury, Md.

[73] Assignee: Dresser Industries, Inc., Dallas, Tex.

[22] Filed: Sept. 23, 1974 [21] Appl. No.: 508,581

[52] US. Cl 141/93; 191/290 [51] Int. Cl. B65b H28 [58] Field of Search 222/4815; 141/93, 291, 141/292, 293, 289, 290

[56] References Cited UNITED STATES PATENTS 3,710,830 l/l973 Gilson 141/93 Pritmlry 1;1\'aml'nerAllen N. Knowles Assistant E \'aminerHadcl Lane Attorney, Agent, or Firm-Roy L, Van Winkle; John N. Hazelwood [451 Aug. 19, 1975 5 7 ABSTRACT A vapor recovery nozzle for dispensing fuel, such as gasoline, that can be latched to the filler neck of a tank to be filled. An articulated seal is provided that sealingly engages the filler neck and, when so engaged, forces a piston relatively toward the nozzle to open the flow passageway through the nozzle for the vapors. A valve is provided that is actuated by the piston which, when the nozzle is not in the tiller neck, closes to prevent the escape of any vapors that might be contained in the vapor recovery system. Further more, the piston carries a valve operating means that functions in conjunction with a flow valve that is located in a conduit extending through the nozzle. This conduit is utilized to sense when the liquid level in the tank rises above the end of the conduit extending from the nozzle to automatically shut off the nozzle and prevent flow of fuel therefrom. The arrangement of the nozzle is such that the vapor recovery passageway extending therethrough is sealed to prevent the entrance of air or other vapor into the system except as may come from the fuel tank.

8 Claims, 4 Drawing Figures SZIZU 1 BF 2 PATENTEU AUG-1 9 I975 VAPOR RECOVERY NOZZLE BACKGROUND OF THE INVENTION This invention relates generally to improved gasoline dispensing nozzles. More particularly, but not by way of limitation, this invention relates to an improved vapor recovery nozzle of the automatic shutoff type.

Due to the volatility of fuels, such as gasoline, considerable vapors "re generated during the filling of fuel tanks and the like. For the most part, and particularly with respect to the filling of automotive fuel tanks, such vapors have been permitted to escape into the atmosphere. As the vapors escape from the tank, they mix with air and upon reaching a specified concentration can form an extremely explosive mixture. The escape of such vapors has become of great concern, not only because of the safety hazard, but more recently because of the concern about pollution of the atmosphere.

It has been proposed to prevent the escape of such vapors into the atmosphere by a use of a nozzle that forms a seal with the filler neck of the fuel tank and has appropriate passageways provided therein for extracting the vapors from the tank as they are generated. U.S. Pat. No. 3,521,679 issued to E. L. Copony on July 28, 1970 describes one such dispensing nozzle. Another dispensing nozzle that has provisions for the removal of such vapors is described in US. Pat. No. 3,823,752 is sued to Donald A. Lasater et al. on July 16, 1974. Both of the above nozzles appear to provide apparatus adequate for the recovery of such vapors. However, it is noted that in most instances, the nozzles must be held, manually, in the filler neck during the filling operation and neither provide any means for preventing the escape of vapors from the vapor recovery system once the delivery has stopped.

A further problem with prior art nozzles is that an effective seal with the tank has not been attained. The difficulty of forming an effective, gas-tight seal results primarily from the wide variety of sizes and configurations of filler necks as well as from the cosmetic treatment given the refueling area of vehicles by the vehicle manufactures.

It is an object of this invention to provide an improved vapor recovery nozzle of the automatic shutoff type. I

It is another object of this invention to provide an improved vapor recovery nozzle that is positively retained in the filler neck during operation.

A further object of the invention is to provide an improved vapor recovery nozzle that includes a sealed vapor passageway from the tank to the vapor recovery system.

SUMMARY OF THE INVENTION This invention provides an improved gasoline dispensing nozzle of the automatic shutoff type for use in connection with vapor recovery systems. The nozzle includes a body containing a flow control valve, induction means for causing gas flow through the nozzle, a trigger for activating the flow control valve and pressure responsive latch means operable in conjunction with the induction means to release the flow control valve regardless of the trigger position. The nozzle also includes an elongate hollow spout, a conduit extending substantially through the interior of the spout for connection with the induction means and valve means for opening and closing the conduit. A hollow member for connecting the spout in fluid communication with the body has an enlarged portion forming a portion of a vapor passageway with the spout and has a port extending therethrough providing fluid communication between the vapor passageway and the vapor recovery system. A hollow piston loosely encircles the spout and forms a portion of the vapor passageway therewith. The piston has a first end portion slidingly and sealingly received in the hollow member and has a second end portion. An articulated seal assembly is located on and movable with the second end of the piston in sealing relationship therewith. The articulated seal assembly forms another portion of the vapor passageway and has a seal member thereon arranged to sealingly engage the projecting surface on the fuel tank whereby the vapor passageway provides communication between the tank and the vapor recovery system. The piston also carries valve operating means that operates the valve to open the conduit when the piston is moved into the hollow member permitting operation of the nozzle.

BRIEF DESCRIPTION OF THE DRAWING FIGS. 1A and 1B taken together comprise a vertical cross-sectional view of a nozzle constructed in accordance with the invention.

FIG. 2 is a view partially in elevation and partially cross section taken generally along the line 22 of FIG. 1A.

FIG. 3 is a partial cross-sectional view of the nozzle of FIGS. 1A and 1B, but showing the various components thereof in another operating position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing and to FIGS. 1A. 1B and 2 in particular, shown therein and generally designated by the reference character 10 is a vapor recovery nozzle constructed in accordance with the invention. The nozzle 10 includes a nozzle body assembly 12, a spout assembly 14, and a handle assembly 16.

The nozzle body assembly 12 has been fully described in US. Pat. No. 3,638,689 issued to Hans Eric Ecklund on Feb. 1, 1972. For this reason, the body as sembly 12 will not be described in great detail but only to the extent necessary to the understanding of the vapor recovery aspects of the nozzle 10.

The nozzle body assembly 12 is hollow and includes a spring loaded main valve assembly 17 disposed in a flow passageway through the valve. The main valve assembly 17 is normally closed and is moved to the open position by pulling upwardly on a trigger 18 which displaces a valve actuating mechanism 20 rearwardly forcing the main valve assembly 17 off its seat.

As can be seen more clearly in FIG. 2, the actuating mechanism 20 includes a diaphragm controlled latch 22. A diaphragm 24 of the latch 22 is displaced inwardly of the no71le body assembly 12 by a spring 26. With the latch 22 in this position, movement of the trigger l8 displaces the main valve 16 off its seat. However, an induction system that includes a conduit 28 located in spout 30, a passageway 32 formed in the body assembly 12, and a passageway 34 that extends from the diaphragm 24 to the throat of the valve seat in main valve assembly 16.

Briefly, and so long as the induction system is unobstructed, gasoline flowing through the nozzle body assembly I2 induces gas to flow through the conduit 28, the passageway 32 and the passageway 34 so that there is no net pressure effect on the diaphragm 24. However, upon obstruction of the conduit 28, a negative pressure is created on the diaphragm 24 displacing the latch 22 out of the valve actuating mechanism and releasing the main valve 16 so that it can reseat shutting off flow through the nozzle 10.

In addition to the conduit 28 and the spout 30, the spout assembly I4 also includes a hollow member 36 having a relatively small end 38 that is screwed into the nozzle body assembly 12 and a relatively large end portion 40 that is sized to slidingly receive a piston 42. It will be noted that the interior of the hollow member 36 is threaded to receive one end of the spout and to retain the spout 30 in concentricity with the large end portion thereof.

A port 44 extends through the side wall of the hollow member 36 providing fluid communication between the interior thereof and a vapor recovery conduit 46 that forms a portion of the handle assembly 16.

As previously mentioned, the conduit 28 forms a portion of the induction system and, as can be clearly seen in FIG. 1A, the upper end of the conduit 28 is connected with a portion of the nozzle body 12. It will be noted in FIG. 1B that the end of the conduit 28 extends through the side wall of the spout 30 near the discharge end of the spout 30 for purposes which will be described hereinafter. Intermediate the ends of the conduit 28, the conduit is provided with an annular valve seat 48 that is arranged to sealingly engage one end of a valve member 50 that is movably located in the conduit 28.

The valve member 50 is movable toward and away from the seat 48 to open and close the conduit 28. The valve member 50 may be constructed from, or at least includes, a ferromagnetic portion having North and South magnetic poles located as shown in FIG. 1B.

The piston 42 is hollow and encircles the spout 30. The interior of a small end 52 on the piston 42 is provided with keyways to receive keys 54 mounted on the exterior of the spout 30 to retain the piston 42 in a predetermined alignment with the spout 30. The piston 42 fits within the large end portion 40 of the hollow member 36 and is slideable therein. To prevent the escape of vapors from within the hollow member 36 and the piston 42, the piston 42 carries a seal 56 that slidingly and sealingly engages the interior of the hollow member 36.

The end of the piston 42 carrying the seal 56 has an enlarged bore 58 to permit the flow of vapors between the spout 30 and the piston 42. On the same end of the piston 42, there is located an annular seal 60 that, in its closed position, abuts a vapor passageway valve member 62 that is mounted on the spout 30. The purpose of the vapor passageway valve which includes the seal 60 and the valve member 62 is to prevent the escape of vapors outwardly from the nozzle 10 when the valve member 62 is in sealing engagement with the seal 60.

A compression spring 63 is located within the hollow member 36 and engages the piston 42 to bias the piston 42 relatively outwardly of the hollow member 36. The engagement between the valve member 62 and seal 60 also functions to limit the outward movement of the piston 42 in the hollow member 36.

The piston 42 is also provided with a ferromagnetic member 64 located adjacent the bore 58 thereof. The

ferromagnetic member 64 is disposed in juxtaposition with the valve member 50 located in the conduit 28. It will be noted, however, that the North and South magnetic poles of the member 64 are oppositely oriented with respect to those in the valve member 50. The purpose of the keyways in the piston 42 and the keys 54 on the conduit 28 is to retain the ferromagnetic member 64 adjacent the valve member 50. With the poles oriented as shown, it will be appreciated that the repelling force developed by adjacent, like poles shown in FIG. 18 will cause the valve member 50 to sealingly engage the seat 48 in the conduit 28, thereby preventing the flow of fluid therethrough.

An articulated seal member 66 is movably connected to the small end 52 of the piston 42 by a pin 68. A seal 70 located in the small end of the seal member 66 forms a flexible, vaportight seal with the exterior of the small end 52 of the piston 42. A large seal 72 located on the opposite end of the seal member 66 is provided to sealingly engage a surface 74 located on a filler neck 76 of the fuel tank as shown in FIG. 3. As illustrated, a garter spring 77 located within the seal 70 aids in maintaining the fluid-tight sealing relationship between the seal 70 and piston 42.

A stop screw 78 or other similar abutment member is mounted on the spout 30. The stop screw 78, as can be seen in FIG. 3, is provided to engage an inner surface 80 on the filler neck 76 to securely retain the nozzle 10 in the filler neck 76.

In addition to the conduit 46, the handle assembly 16 includes a guard 82 that is arranged to protect the trigger mechanism 18 and also carry a second conduit 84 that is in fluid communication with the conduit 46 and thus with the vapor recovery passageway that extends through the nozzle 10. The opposite end of the conduit 84 will be connected with a vapor recovery system (not shown) that is provided to remove the vapors being generated during the filling of the tank with fuel.

OPERATION OF THE PREFERRED EMBODIMENT In operation, the nozzle 10 is connected via the threads at one end of the nozzle body 12 by a fuel supply (not shown) and the conduit 84 will be connected into a vapor recovery system (not shown). The fuel supply will be provided with a pump (not shown) that will deliver liquid fuel to the nozzle 10 under pressure.

The nozzle 10 is removed from the fuel dispenser and the spout 30 inserted in the filler neck 76 of a tank to be filled as illustrated in FIG. 3. Force is applied to the nozzle 10, placing the seal 72 in sealing engagement with the surface 74 on the filler neck 76, displacing the piston 42 into the hollow body 36 and compressing the Spring 63. The stop screw 78 passes through the opening in the filler neck 76 and is brought into engagement with the surface 80 thereon locking the nozzle 10 into the filler neck 76, relieving the operator from the necessity of holding the nozzle during the filling opera tion. It should be noted that the seal 72 is very little larger than the size of the filler neck 76, thus providing for the desired sealing engagement regardless of the cosmetic treatment of the vehicle surrounding the filler neck.

Simultaneously, the seal 60, which is carried by the piston 42, is displaced inwardly and away from the vapor passageway valve member 62 thereby opening the vapor passageway extending through the nozzle to the flow of vapor. It can be appreciated that vapor leaving the tiller neck 76 passes through the opening therein, through the piston 42, past the vapor passageway valve member 62 and seal 60, and into the interior of the hollow body member 36. The vapors then pass outwardly through the port 44 in the hollow member 36 into the conduits 46 and 84 and into the vapor recovery system.

Displacement of the piston 42 into the hollow member 36 also moves the ferromagnetic member 64 until the North magnetic pole thereon is disposed adjacent the North magnetic pole on the valve member 50 which is located in the conduit 28. When the North poles align, the opposing force generated thereby displaces the valve member 50 away from the seat 48 in the conduit 28 opening the conduit 28 to flow.

The person operating the nozzle then grips the trigger 18 which moves the valve actuating mechanism 20 rearwardly, that is, to the right as seen in FIG. 1A, opening the main valve 17 to the flow of fuel. As fuel flows through the nozzle body 12 and outwardly through the spout 30 into the tank, a slight negative pressure is generated in the induction system moving gas through the passageways 34, 32 and through the conduit 28. So long the conduit 28 remains open, this slight pressure reduction is not sufficient to displace the diaphragm 24 and latch mechanism 22 out of the valve actuating mechanism 20 and, thus, the nozzle will continue to remain open to provide fuel flow into the tank.

As previously mentioned, vapors generated in the tank flow upwardly through the filler neck 76 through the sealed vapor passageway system provided in the piston 42 and hollow member 36 and outwardly into the vapor recovery system through the conduits 46 and 48.

As the tank fills, the liquid fuel will eventually reach the lower end of the conduit 28 blocking the conduit 28 against further gas flow. When this occurs, the negative pressure in the induction system is considerably increased and reaches the point at which the diaphragm 24 is pulled relatively downwardly (see FIG. 2) displacing the latch mechanism 22 out of the valve actuating mechanism 20. The valve actuating mechanism 20 can then collapse permitting the spring-loaded main valve 17 to close despite the fact that the trigger mechanism 18 may still be in a position wherein the valve 17 would normally be open.

It will be apparent from the foregoing, that so long as the conduit 28 remains blocked, any effort to deliver additional fuel into the tank will be fruitless since the main valve 17 cannot be moved off of its seat.

After the tank has been filled, a slight force is exerted on the nozzle 10 moving the stop screw 78 free of the filler neck 76. The nozzle 10 can then be removed from the filler neck 76. As this occurs, the spring 63 displaces the piston 42 relatively outwardly of the hollow member 36 until the seal 60 engages the vapor passageway valve member 62. Upon closure of the vapor passageway valve, any vapors contained in the vapor recovery system including the conduits 46 and 48 will be trapped therein.

Simultaneously, the ferromagnetic member 64 has moved with the piston 42 until the South magnetic pole thereon is aligned with the South magnetic pole in the valve member 50. With the poles aligned in this manner. the valve member 50 is driven against the seat 48 blocking the conduit 28 and preventing further delivery of fuel through the nozzle 10 until the nozzle 10 is inserted in a tank wherein the fuel level is sufficiently low to clear the conduit 28.

From the foregoing detailed description of the invention, it will be appreciated that the vapor recovery nozzle 10 provides: a means of positively forming a seal with the tiller neck 76; a sealed vapor recovery passagewayextending through the nozzle; means for entrapping the vapors recovered in the system; and, a positive means for latching the vapor recovery nozzle 10 into the filler neck of the tank to be filled.

It will also be understood that the detailed description of the preferred embodiment is presented by way of example only and that many changes and modifications can be made thereto without departing from the spirit or scope of the invention.

The embodiments of the invention in which an exclu sive property or privilege is claimed are defined as follows:

1. An improved gasoline dispensing nozzle of the automatic shut-off type for use in connection with vapor recovery systems including a body containing a flow control valve, induction means for causing gas flow through a nozzle, a trigger for activating the flow control valve and pressure responsive latch means operable in conjunction with the induction means to release the flow control valve regardless of the trigger position, the improvement comprising:

an elongate hollow spout;

a conduit extending substantially through the interior of said spout for connection with the induction means and including valve means for opening and closing said conduit;

a hollow member for connecting said spout in fluid communication with the body and having an enlarged portion forming a portion of a vapor passageway with said spout and a port therethrough providing fluid communication between said vapor passageway and vapor recovery system; I

a hollow piston loosely encircling said spout and forming a portion of said vapor passageway therewith, said piston having a first end portion slidingly and sealingly received in said hollow member and having a second end portion;

an articulated seal assembly located on and movable with the second end of said piston in sealing relationship therewith and loosely encircling said spout, said assembly forming another portion of the vapor passageway having a seal member thereon arranged to sealingly engage a projecting surface on a tank to be filled whereby said vapor passageway provides communication between the tank and vapor recovery system; and,

valve operating means carried by said piston for operating said valve means to open said conduit when said piston is moved into said hollow member permitting operation of said nozzle and operating said valve means to close said conduit preventing oper ation of said nozzle.

2. The improved nozzle of claim 1 and also including:

spring means in said hollow member for biasing said piston and seal assembly outwardly of said hollow member; and,

stop means on said spout outwardly of said seal assembly for engaging the tank to be filled, whereby said nozzle is securely retained in said tank with the seal member in sealing engagement with the projecting surface thereon.

3. The improved nozzle of claim I wherein said valve means includes an annular valve seat in said conduit and a valve member movable into and out of engagement with said seat to open and close said conduit.

4. The improved nozzle of claim 3 wherein:

said valve member includes North and South mag netic poles; and,

said valve operating means includes North and South magnetic poles disposed in juxtaposition to, but oppositely oriented with respect to the poles of said valve member.

5. The improved nozzle of claim 1 and also including:

vapor passageway valve means on said spout and piston for closing said vapor passageway when said nozzle is not engaging the tank.

6. The improved nozzle of claim 5 wherein said vapor passageway valve means includes:

an annular seal member carried by and located internally of said piston; and.

an annular abutment of said spout located internally of said piston and arranged to engage said annular seal member to close said vapor passageway when said nozzle is not engaging the tank and to limit the relative outward movement of said piston from said hollow member.

7. The improved nozzle of claim 1 wherein said articulated seal assembly also includes:

a relatively rigid seal body encircling said spout and piston and supporting said seal member; connecting means attaching said seal body to said piston for movement therewith and permitting limited articulation of said seal body relative to said piston; and, flexible seal means on said seal body sealingly engaging said piston in all positions of said seal body relative to said piston.

8. The improved nozzle ofclaim 7 and also including:

spring means in said hollow member for biasing said piston and seal assembly outwardly of said hollow member;

stop means on said spout outwardly of said seal assembly for engaging the tank to be filled, whereby said nozzle is securely retained in said tank with the seal member in sealing engagement with the pro jecting surface thereon;

vapor passageway valve means for closing said vapor passageway when said nozzle is not engaging the tank, said vapor passageway valve means including an annular seal carried by and located internally of said piston, and an annular abutment of said spout located internally of said piston and arranged to engage said annular seal member to close said vapor passageway and to limit the relative outward movement of said piston from said hollow member; and, wherein said valve means includes an annular valve seat in said conduit and a valve member having North and South magnetic poles, said valve member being movable into and out of engagement with said valve seat to open and close said conduit; and,

said valve operating means includes North and South magnetic poles in juxtaposition to, but oppositely oriented with respect to the poles of said valve member, whereby the magnetic poles on said valve operating means are located in opposition to the poles of said valve member holding said valve member on or off said seat due to the repulsing forces generated by said magnetic poles.

l l l l 

1. An improved gasoline dispensing nozzle of the automatic shutoff type for use in connection with vapor recovery systems including a body containing a flow control valve, induction means for causing gas flow through a nozzle, a trigger for activating the flow control valve and pressure responsive latch means operable in conjunction with the induction means to release the flow control valve regardless of the trigger position, the improvement comprising: an elongate hollow spout; a conduit extending substantially through the interior of said spout for connection with the induction means and including valve means for opening and closing said conduit; a holLow member for connecting said spout in fluid communication with the body and having an enlarged portion forming a portion of a vapor passageway with said spout and a port therethrough providing fluid communication between said vapor passageway and vapor recovery system; a hollow piston loosely encircling said spout and forming a portion of said vapor passageway therewith, said piston having a first end portion slidingly and sealingly received in said hollow member and having a second end portion; an articulated seal assembly located on and movable with the second end of said piston in sealing relationship therewith and loosely encircling said spout, said assembly forming another portion of the vapor passageway having a seal member thereon arranged to sealingly engage a projecting surface on a tank to be filled whereby said vapor passageway provides communication between the tank and vapor recovery system; and, valve operating means carried by said piston for operating said valve means to open said conduit when said piston is moved into said hollow member permitting operation of said nozzle and operating said valve means to close said conduit preventing operation of said nozzle.
 2. The improved nozzle of claim 1 and also including: spring means in said hollow member for biasing said piston and seal assembly outwardly of said hollow member; and, stop means on said spout outwardly of said seal assembly for engaging the tank to be filled, whereby said nozzle is securely retained in said tank with the seal member in sealing engagement with the projecting surface thereon.
 3. The improved nozzle of claim 1 wherein said valve means includes an annular valve seat in said conduit and a valve member movable into and out of engagement with said seat to open and close said conduit.
 4. The improved nozzle of claim 3 wherein: said valve member includes North and South magnetic poles; and, said valve operating means includes North and South magnetic poles disposed in juxtaposition to, but oppositely oriented with respect to the poles of said valve member.
 5. The improved nozzle of claim 1 and also including: vapor passageway valve means on said spout and piston for closing said vapor passageway when said nozzle is not engaging the tank.
 6. The improved nozzle of claim 5 wherein said vapor passageway valve means includes: an annular seal member carried by and located internally of said piston; and, an annular abutment of said spout located internally of said piston and arranged to engage said annular seal member to close said vapor passageway when said nozzle is not engaging the tank and to limit the relative outward movement of said piston from said hollow member.
 7. The improved nozzle of claim 1 wherein said articulated seal assembly also includes: a relatively rigid seal body encircling said spout and piston and supporting said seal member; connecting means attaching said seal body to said piston for movement therewith and permitting limited articulation of said seal body relative to said piston; and, flexible seal means on said seal body sealingly engaging said piston in all positions of said seal body relative to said piston.
 8. The improved nozzle of claim 7 and also including: spring means in said hollow member for biasing said piston and seal assembly outwardly of said hollow member; stop means on said spout outwardly of said seal assembly for engaging the tank to be filled, whereby said nozzle is securely retained in said tank with the seal member in sealing engagement with the projecting surface thereon; vapor passageway valve means for closing said vapor passageway when said nozzle is not engaging the tank, said vapor passageway valve means including an annular seal carried by and located internally of said piston, and an annular abutment of said spout located internally of said piston and arranged to engage said annular seal member to close said vapor passageway and to lImit the relative outward movement of said piston from said hollow member; and, wherein said valve means includes an annular valve seat in said conduit and a valve member having North and South magnetic poles, said valve member being movable into and out of engagement with said valve seat to open and close said conduit; and, said valve operating means includes North and South magnetic poles in juxtaposition to, but oppositely oriented with respect to the poles of said valve member, whereby the magnetic poles on said valve operating means are located in opposition to the poles of said valve member holding said valve member on or off said seat due to the repulsing forces generated by said magnetic poles. 